1. Field of the Invention
This invention generally relates to the field of items processing. More specifically, the present invention relates to a conveyance unit that conveys a group of items received at an upstream side placing location to a downstream side discharge location, while holding such items group in a predetermined position. The present invention further relates to a boxing unit having such conveyance unit.
2. Background Information
Generally, food items such as potato chips are first packaged in bags and then conveyed to a boxing station by a conveyance apparatus. Then, the bags are boxed in cardboard boxes at the boxing station.
In recent years, there has been an effort in the field of items-conveyance technology to increase productivity by increasing the processing speed. Japanese Laid-Open Patent Application H5-278840 discloses an example of such a conveyance apparatus. As shown in FIG. 14, the conveyance apparatus A has first and second chains B1 and B2, which are annular and parallel to each other. The first and second chains B1 and B2 are disposed parallel to the conveyance direction of the items X . . . X, which is indicated by the arrow. Each of the chains B1 and B2 is driven independently by drive means not shown in the figure. Each of the chains B1 and B2 has a plurality of partition members C . . . C, which are disposed with a predetermined space therebetween. These partition members C . . . C form a pair of first items-holder groups D11 and D12 on the first chain B1 and a pair of second items-holder groups D21 and D22 on the second chain B2. Each of the pairs holds a predetermined number of items (ten in FIG. 14). The first items-holder groups D11 and D12 and the second items-holder groups D21 and D22 are disposed alternately in the conveyance direction.
In this manner, for instance, one of the first items-holder groups D11, which is conveyed intermittently by the first chain B1, receives ten items X . . . X from an upstream side loading conveyer E at the receiving position P1. During the placing, the other of the first items-holder groups D12 is finished with the discharge of items X . . . X, and starts moving toward the receiving position P1, being conveyed intermittently on the position shown in FIG. 14.
Meanwhile, one of the second items-holder groups D21, which has already received ten items X . . . X, is stopped at the discharge position P2 having been conveyed there by the second chain B2. A comb-shaped pusher F discharges the items X . . . X from the second items-holder group D21 all at once. During the discharge, the other of the second items-holder groups D22 is on its way to the receiving position P1, being stopped at the position shown in the Figure.
Once the second items-holder group D21 is finished with the discharge, the second items-holder group D21 starts moving toward the receiving position P1. Also, once the first items-holder group D1 is finished with the loading, the first items-holder group D11 starts moving toward the discharge position P2, where the items X . . . X are discharged. After the first items-holder group D11 leaves the receiving position P1, the second items-holder group D22 arrives at the receiving position P1, where it receives the items X . . . X from the loading conveyer E.
Through the repeating of such operations by each of the items-holder groups D11, D12, D21, and D22, it is possible to perform placing, conveyance, and discharge of the items X . . . X efficiently. As a result, it is possible to increase the speed with which the items X . . . X are processed.
In another example of a conveyance apparatus, Japanese Laid-Open Patent Application H9-104526 discloses a conveyance apparatus formed without a plurality of partitioning members, where, after a plurality of bagged items are received, these items are conveyed as a group and discharged at a discharging position as a group. As shown in FIG. 15, in this conveyance apparatus G, items X . . . X, which were loaded from an upstream loader conveyer H in a sideways position, are put into an upright position by the uprighting action, as indicated by the broken lines, of pallets J . . . J provided on an uprighting apparatus I at receiving position P1. The items X . . . X are lined up into a single line by the engagement of the tabs thereon with pole-shaped guide rails K1, K2, which are disposed to the left and right of and horizontally along the conveyance direction as indicated by the arrow in the figure. Thus the items X . . . X are kept pressed close to one another.
Then, the items X . . . X are conveyed to a discharge position P2 by a plate-shaped upright-position pusher L that moves in the manner shown by the broken lines, such conveyance being facilitated through the engagement of the right guide rail K2 and a rear guide rail K3 disposed to succeed the left guide rail K1. When the lead item X comes in contact with a stopper M, the items group X . . . X is discharged by a sheet-shaped sideways-position pusher N toward a cardboard box that is not shown in the drawing.
This conveyance apparatus G does not use partitioning members. Such a design allows the apparatus to be flexible in terms of both the dimensions of items it conveys, as well as the number of individual pieces conveyed as an items group X . . . X.
However, both the conveyance apparatuses A and G give rise to the following problems.
In the conveyance apparatus A described in Japanese Laid-open Patent Application H5-278840, the partition members C . . . C are fixedly coupled to the first and second chains B1 and B2. Therefore, in certain cases, when the type of items to be conveyed has been changed, the number of partition members C . . . C or the space between the partition members C . . . C must be changed in accordance with the thickness of the items X . . . X, as well as the number of the items X . . . X in a group. With this conveyance apparatus A, such change cannot be made right away; furthermore, the labor expended to make the change is burdensome.
In addition, because the items X . . . X are held by the plurality of partition members C . . . C, the dimensions of the item-holding spaces are usually made larger than the dimensions of the items X . . . X, given the variation in the thickness of the items X . . . X. Therefore, in order to pack the items-group X . . . X compactly into a cardboard box when the items X . . . X are discharged at the discharge position P2, there is the additional task of packing the items more tightly. This can lead to various problems such as the items X . . . X falling over or becoming disarrayed, or the bags being torn.
Meanwhile, in the conveyance apparatus G described in Japanese Laid-open Patent Application 9-104526, because the items X . . . X are conveyed through the engagement of the tabs on the items X . . . X with the guide rails K1, K2 and K3, only items that have tabs capable of engaging with these guide rails K1, K2, and K3 can be conveyed.
In addition, because there is no member to support the lead item X from the front, the items X . . . X are not held in a stable position, and this will lead to problems, particularly in cases where high-speed conveyance is required. Furthermore, during conveyance, the bottoms of the items X . . . X move along a table O, and the conveyance cannot be expected to be smooth.
In addition, in order to prevent the sideways-position pusher N and the guide rail K3 from becoming entangled with each other when the pusher N discharges the items group X . . . X toward a cardboard box, a mechanism is provided that moves the rear guide rail K3 upwards, and this increases the cost.
In view of the above, there exists a need for conveyance apparatus which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.